1) Field of the Invention
The present invention relates to a colored laminated glass, namely, a colored glass laminate and a production process thereof. More specifically, the present invention is concerned with a colored glass laminate excellent in light resistance and the like and its production process.
2) Description of the Related Art
Colored glass laminates have been increasingly finding utility as window glass for various buildings, automobiles, etc.
These colored glass laminates are produced by sandwiching a colored polyvinyl butyral film between two glass plates. This production process is however accompanied by the problem of being unable to provide colored glass laminate of large dimensions.
Another production process has recently been introduced, in which a colored glass laminate of large dimensions is produced by arranging a spacer between two glass plates, pouring a monomer into the spacing defined by the spacer and then polymerizing the monomer. As a method for coloring glass in accordance with this process, a dye may be dissolved in the monomer. However, a dye is generally inferior in light resistance. Glass laminates produced by this process therefore have a color fastness problem when used as window glass for exterior walls of buildings.
Such a problem can be overcome by the use of a pigment as a colorant. A pigment is however insoluble in a liquid and therefore undergoes settling in a monomer liquid, inducing such problems as reduced coloring power and irregular color density.
Such a dispersibility problem of a pigment can generally be resolved by a surfactant. In the case of coloring of a monomer liquid for a glass laminate, the concentration of the pigment is very low, usually, 1.0% or less, leading to the problem that no sufficient dispersion stability can be achieved by a conventional surfactant. For these reasons, no pigment-colored glass laminates have yet been known to date.